Poly(alkanoyl isosorbide methacrylate)s: From Amorphous to Semicrystalline and Liquid Crystalline Biobased Materials.

We have prepared a series of 12 d-isosorbide-2-alkanoate-5-methacrylate monomers as single regioisomers with different pendant linear C2-C20 alkanoyl chains using biocatalytic and chemical acylations. By conventional radical polymerization, these monomers provided high-molecular-weight biobased poly(alkanoyl isosorbide methacrylate)s (PAIMAs). Samples with C2-C12 alkanoyl chains were amorphous with glass transition temperatures from 107 to 54 °C, while C14-C20 chains provided semicrystalline materials with melting points up to 59 °C.

An NMR and MD modeling insight into nucleation of 1,2-alkanediols: selective crystallization of lipase-catalytically resolved enantiomers from the reaction mixtures.

The work on developing a scalable lipase-catalytic method for the kinetic resolution of long-chain 1,2-alkanediols, complemented by crystallization of the pure enantiomers from the reaction mixtures, offered the possibility of a more detailed study of the aggregation of such diols. MD modeling, mass spectrometry, (1)H NMR, and DOSY studies provided a novel insight into the nucleation process. An efficient protocol for stereo- and chemoselective crystallization of (S)-1,2-dodecanediol and related compounds from the crude bioconversion mixtures was developed.

Synthesis and quantitative analysis of diastereomeric linked ester conjugates with remote stereocenters using high-field NMR and chiral HPLC.

A stereochemically safe high-yielding procedure for linking unprotected as well as protected hydroxycarboxylic acids to chiral secondary alcohols via glycolic acid linker is proposed. L-menthol has been linked with both enantiomers of mandelic, malic, and methoxyphenylacetic acid using bromo- or iodoacetyl group as a precursor of the glycolic acid linker. High-field nuclear magnetic resonance (NMR) and chiral high-performance liquid chromatography (HPLC) determination of high diastereomeric ratio (dr) (>99%) of the products bearing remote stereocenters was explored.

Theoretical prediction and assignment of vicinal 1H-1H coupling constants of diastereomeric 3-alkoxy-6,7-epoxy-2-oxabicyclo[3.3.0]octanes.

Spin-spin coupling constants between nuclei in NMR spectroscopy reflect their spatial arrangement. A number of calculation methods, applying different levels of theory, have been developed to support the stereochemical assignment of novel compounds. Nevertheless, revisions of the assignment of structures in the literature are not rare.

Synthesis of deoxy sugar esters: a chemoenzymatic stereoselective approach affording deoxy sugar derivatives also in the form of aldehyde.

A chemoenzymatic synthesis of deoxy sugar esters is described. The synthesis is based on the O-alkylation of carboxylic acid with 2-bromo-5-acetoxypentanal. The method allows treatment of hydroxy carboxylic acids without protection of alcoholic hydroxyl groups.